gnss rfi mitigation: european efforts & proposals european organisation for the safety of air...
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The European Organisation for the Safety of Air Navigation
GNSS RFI Mitigation:
European Efforts & Proposals
Pascal BARRET & Gerhard BERZ
ATM Directorate, Research & SESAR Division, NAV & CNS Unit
Civil GPS Service Interface Committee
Tampa, 14 September 2015
2
Overview
• GNSS RFI Mitigation Plan Development
• Introduction & Principles
• Implementation Support
• Threat Monitoring and Risk Assessment: Global and Regional
Processes (Short Term)
• Long Term Strategic Objective
Note: Developed through SESAR
Introduction
• GNSS RFI Mitigation Plan History & Context
• Initiated by Spring 2013 Workshop at Eurocontrol Navigation
Steering Group Meeting
• Guidance developed through ICAO Navigation Systems Panel
• In response to ICAO 12th Air Navigation Conference Job Card
• Proposed for inclusion in GNSS Manual, ICAO DOC 9849
• Dec 2015 Change Package
• Beginning of document very technical (definitions and
classification), but rest should be accessible to general audience
• Scope
• Limited to threats requiring radio frequency propagation
• Not dealing with corruption of position once it has left receiver
Moving from Vulnerability to Mitigation
• Objective of RFI Mitigation Plan
• Define set of activities for States to ensure that risks to
aviation from GNSS RFI are sufficiently mitigated
• Checklists of set of activities to be considered
• Much is already in place, State to decide depending on local
environment
• To enable reliance on GNSS and associated aviation benefits
• Focused on States
• Spectrum a sovereign responsibility
• Regulation and enforcement part of national oversight
• Framework to encourage coordination and exchange of best
practices
• Current work focused on regional and global support
4
Mitigation Plan Framework
5
Monitor Threats Proactive & Reactive
Monitoring
Environment Evolution
1
Assess Risks Scenario Variation &
Escalation
Impact Assessment
Identify Existing Barriers
2
Deploy Mitigation
Measures Reduce Risks to Acceptable Levels
Integrate in Safety Management System
3
Risk Trade Space
Pro
bab
ility
Severity
Normal Events,
Limited Severity
Un
pre
dic
tab
le
Cata
str
op
hic
Even
t
If probability difficult to
quantify, only approach is
to limit impact
Implementing Mitigation Barriers
Prevent
Transmission of
RFI
- Regulatory Control
and Enforcement
- Outreach
GNSS RFI Vulnerability
Limit Severity of
Impact
- CNS/ATM Integration
- A-PNT
- Detection &
Resolution
Prevent GNSS
Service Outage
- GNSS Resilience
- On-board Integration
Supported by (Reactive)
Threat Monitoring Networks
Starting Challenges
• Observability: Difficult to get data on incidents
• Existing Spectrum Groups receive few reports
• NOTAM search produced few results
• Event Confirmation:
• Difficult to conclude that GNSS outage is result of RFI
• Event Scope
• Difficult to quantify geographical extent, duration and impact
• Best to monitor at the impact source: aircraft receiver
• Currently, only pilot can observe receiver outage
• Subsequent reporting requires support at regional and global level
• Ground networks useful complement, but limited use
• Apart from visibility issues, lacks essential risk assessment link:
what is the impact at the aircraft?
8
Identification of Probable Cause
Through Elimination
9
Reported GNSS
Outage Event
Due to
Constellation
/ Satellite ?
- CSP Centers (GPS
NAVCEN, etc.)
- Augmentation User
Support (ESSP, etc.)
- Space Wx Agencies
- Iono Monitoring
Networks
- Receiver
Manufacturers
- Avionics Integrators
- Civil-Military
Coordination, NATO
- National Defense - Local Verification &
Resolution
Due to
Receiver
Problem ?
Due to Space
Weather ?
If all else can
be excluded,
must be RFI !
Due to
Military
Testing ?
GPS OUT Reporting Streams Today
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Airline OPS Center
FOQA Monitoring?
PIREP: Local AIS
AO
Local ANSP ? AIS to Technical Services
Technical Services activate
subsequent process?
ESSP
GPS
NAVCEN
GNSS Multi-Modal Aviation one User among
many
IATA
Eurocontrol
Network
Manager
Aviation Specific GNSS Out One Issue
among many
No aggregate vision of events Incomplete threat picture
Resolution depends on awareness of many individuals
First Step: Align
Aviation Coordination
Second Step:
Interfaces with
GNSS System
Providers
Implemented: GNSS in EVAIR
• EVAIR = Eurocontrol Voluntary ATM Incident Reporting www.eurocontrol.int/services/evair
• Established Safety Process (Confidentiality, Anonymity)
• 250 Participating Aircraft Operators
• Coverage: Europe, Middle East, Northern Africa
• Close cooperation with IATA
• Part of Network Manager Functions
• Info Bulletin / Request sent beginning 2015
• Initial wave of reports received covering 2013/2014
• Additional reports coming in every few weeks
• GNSS Outage one issue among many
• Simple to set up because it is an existing process / framework
• Working on further awareness materials 11
GPS Issues: EVAIR Findings
16/09/2015 12
(Status May 2015)
First reports received in 2013
# of reports in the DB - 42
# of AOs (Aircraft Operator) reporting GPS outages so far - 11
# of locations identified – 17
En-route flight phase most affected
16/09/2015 13
Type of reported GPS issues 2013 – 2014
Loss of GPS Signal
GPS Outage
GPS Jamming
Total Loss of GPS
GPS 1 and 2 Lost
GPS 1 Lost
GPS Issues: EVAIR Findings
GNSS in EVAIR: Threat Monitoring
• Return to normal operations & impact on both receivers on few
aircraft point to RFI with high probability
• Proves that RFI Outages are REAL but also limited in operational
impact currently
• Time-limited, single events do not warrant action
• Supports strategic objective of threat monitoring
• Enables setting boundaries on event probability and severity
• Provides detection if environment changes
• Maintain central repository and statistics of GNSS Outage events
• Consultation of GNSS service and space weather monitoring reports
provides further refinement
• May also benefit from data from local ground receivers
• Clarify interfaces for aviation-relevant reporting
14
EVAIR: GPS Issues Information Flow
16/09/2015 15
EVAIR-
GPS
focal
point
Review
Yes, potential
issue
“GPS
Group”
Review &
Next Step
Heads-up to
AO’s
Notify
ANSP(s)
No Action (await more reports)
NM
Coordination
EASA
No
issu
es
Inform if important
No
issu
es
Heads-up to
Other
Stakeholders
ECTL NM internal
Determine probable
cause through
consultation with GNSS
channels
EVAIR: Trigger for Detection & Mitigation
• Significant accumulation of events in specific area leads to
detection and triggers mitigation action
• Ensuring timely resolution reduces vulnerability / exposure
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Detection by
EVAIR
Local ANSP
- Confirm RFI Case
Pilot / Voice Reports
3rd Party Reports
Deploy Operational
Contingency Measures
Publish NOTAM if reqd.
Locate & Eliminate Source
in cooperation with local
regulatory & enforcement
authorities
Inform AO’s
Interfaces with GNSS System
Operators (GSO)
• Currently, mainly GPS NAVCEN and ESSP
• Multi-constellation: GLONASS, Galileo, Beidou Service Centers
• Regional SBAS User Support Centers (GBAS with local ANSP)
• Case 1: Strategic Long Term Threat Monitoring
• Info from GSO to Aviation: Ensure comprehensive view of all
aviation-relevant cases
• Case 2: Tactical Mitigation: Actual Significant Outage Event
• Request from Aviation to GSO: Support in identifying
probable cause
• Benefit from established links (receiver issues, ionosphere,
RFI testing)
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Medium Term Improvements
• Not really Pilot’s job to determine cause of GPS outage or to report
signal in space issues
• In the age of SWIM, reporting should be automated
• GPS Outage Simulation: ATCO & Planners want to know geographic
extent, start and end of outage (Budapest simulation outcome)
• Reporting through ADS-B Figure of Merit
• Part of ongoing SESAR investigations
• Feasibility demonstration: Australia (Sydney case)
• Need to build experience in how to integrate information
• Some guessing remains with respect to probable cause
• Especially for wide-area outage where resolution should be fast
• Implement RFI detection standard feature in all receivers ?
18
Long Term RFI Mitigation Improvements
• A lot can be done with current capabilities at reasonable cost
• EVAIR is available now
• Mostly a matter of setting up interfaces and data integration
• ADS-B FoM Monitoring excellent example of CNS synergy use
without introducing additional complexity
• Still want to reduce guesswork in future equipment
• Next Generation MC GNSS Avionics
• ICAO NSP requested implementation of reasonable mitigation
capabilities from RTCA / EUROCAE
• Detection capability seen as a feasible minimum:
• Permit aircraft to switch to “A-PNT capability”
• Information must reach ANSP
• Quick Access Recorder, Flight Operations Quality Monitoring
• Future: SUR Downlink Aircraft Parameters (DAP) ??
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Proposed Actions for CGSIC Consideration
1. Support Aviation GNSS RFI Mitigation Plan
• Aviation-relevant threat monitoring & event resolution
• May be suitable for other transport modes & user segments also
2. Support Setup & Alignment of Global Interfaces
• Encourage EVAIR example to be used in other regions
• Requires channels which can handle sensitive information
• Multi-constellation GNSS will increase complexity & need for global
exchange
3. Support strategic long term objective: Closed-loop service
provision for space based infrastructure
• Detect signal-in-space issues at receiver without requiring pilot
intervention
• Provide means to make information available to ANSP & radio
authorities with goal to reduce intervention times
• Investigate best options to support future implementation
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